A mowing unit of a riding mower is typically provided with a height adjusting mechanism for manually selecting the grass cutting height of the mowing unit. JP2015-084710A discloses a mower provided with a mowing unit fitted with a height adjusting mechanism that may be manually operated with a lever or operated by a power actuator via a link mechanism.
A passenger vehicle is often equipped with an independent suspension system in view of maximizing riding comfort. However, in the case of riding power equipment such as a riding mower, a rigid axle suspension system is most commonly used because of high robustness and low cost. If the axle is rigidly attached to the vehicle body, one of the wheels may be lifted from the ground when traveling over an irregular ground surface. To overcome this problem, the axle of the rear wheels or the front wheels may be pivotally supported by the vehicle body at a central point thereof. This system is referred to as “center pivot system” in the following disclosure.
According to the center pivot system, when one of the wheels rides over a bump or drops into a dip, the axle tilts laterally in a corresponding manner, and a lower part of the vehicle body may come excessively close to the ground surface. In particular, if the distance between the cutting blade provided on the bottom side of the vehicle body and the ground surface changes, the grass cutting height changes, and this impairs the grass cutting performance of the mower. If the bottom side of the vehicle body comes excessively close to the ground surface, the cutting blade may hit the ground, and this impairs the durability of the cutting blade.